Nice looking project and cute name. Part of me thinks I'd rather just control hardware directly via the Raspberry Pi, but the I/O is rather limited which means that one would probably have to have some type of I/O extender chip anyways (GPIO mux, I2C or SPI).
On the other hand, with an AVR ATMega connected running Arduino code, you would get that extra I/O (including ADC) and get the benefit of the existing Arduino ecosystem. It remains to be seen how "easy" it will be for beginners to directly control I/O from the Raspberry Pi (like accessing GPIO via the /sys filesystem). I wonder if the Raspberry Pi will be able to run the avrdude and the Arduino IDE (which is Java). If not, then it would annoy me to have to develop for Arduino on a separate PC (and the whole point of RPi is that you don't need an "expensive" PC).
